Manufacture of artificial materials



Nov. 7, 1939. H. DREYFUS ET AL 2178.743

MANUFACTURE OF ARTIFICIAL MATERIALS Filed May 12,. 1938 HENRY DREYFUS ROBERT wmowcmm:

\NVENTD 5 ATTORNEY;

Patented Nov. 7, 1 39 UNITED STATES PATENT OFF-ICE MANUFACTURE OF ARTIFICIAL MATERIALS Henry Dreyfus, London, and Robert Wighton Moncrieff, Spondon, near Derby, England, assignors to Celanose Corporation of America, a corporation of Delaware Application May 12, 1938, Serial No. 207,579 In Great Britain May 21, 1937 10 Claims.

According to the present invention, artificial filaments, foils, films and similar materials, particularly such materials having a basis of cellulose acetate or other organic derivative of cellu lose, are stretched during their travel from one point to another with the aid of a liquid medium which is at a temperature above its boiling point at atmospheric pressure and which is contained in a closed or substantially, closed vessel and maintained under a pressure greater than that corresponding to its vapour pressure at the said temperature by means of air or other gas in the vessel.

A stretching apparatus for use according to the present invention may comprise a closed or substantially closed vessel provided with means for introducing or circulating hot water or other stretching medium into or through the bottom portion or through a container positioned in the vessel, 'feed and delivery devices arranged to guide the materials through the medium, an inlet for compressed air or other gas, a pressure gauge and a pressure release valve. Provision may be made for supply and take-up bobbins inside a closed vessel, or the vessel may be provided with small orifices through which the materials can pass into and out of the vessel. The feed and delivery devices may for example be two pairs of nip rollers or two pairs of rollers arranged so that the rollers of each pair do not contact but the materials make sufliciently large arcs of contact with the rollers to avoid slip. The apparatus may contain a steam coil or other device for controlling the temperature of the medium in the vessel. Preferably nip rollers are arranged so that the materials do not enter the medium until they have left the nip of the feed device and leave the medium before they enter the nip of the delivery device. The bottom roller of each pair may, for example, be immersed to a depth of 1 or 2 inches in the stretching medium.

The apparatus may comprise means for maintaining the materials in an unsoftened condition before they enter the stretching medium and after they leave it. This means may consist of jets through which cold water or cold air may be directed on to the materials. sprayed on to the materi ls, catch trays may be provided underneath the materials, the trays being fitted with outlet pipes which lead to the ex- If-water is to be terior of the vessel and which are provided with pressure release valves in order that the pressure within the vessel may be maintained. Alternatively, the apparatus may be provided with trays or the like to contain cold water through which the materials pass, suitable feed pipes and over-' flow pipes connected with pressure release valves as described above being provided for,the supply and removal of water.

Instead of directing the materials through the medium'by means of the feed and delivery devices, these devices may be above the level of the stretching medium or one or both may be positioned outside the stretching vessel, guide rods or freely mounted guide rollers being positioned in the vessel around which guides the materials pass during their passage from the feed device through the stretching medium to the delivery surface.

Another form of apparatus which may be employed according to the present invention consists of an apparatus similar to that described above but provided with means for cooling the atmosphere instead of applying. a cooling fluid directly to the materials. The cooling means may comprise pipes through which cold water or other cooling fluid is circulated, and which are preferably positioned mainly in the vicinity of the path of the materials between the inlet orifices and the stretching medium and between the stretching medium and the outlet orifices, and which may be arranged both above and below the path of the materials. The apparatus preferably also contains shields to prevent any condensed stretching medium from collecting on the materials during their passage through the vessel, while further shields may be provided underneath the path of the materials through the atmosphere in the vessel in order to assist in preventing vapour from reaching them.

Instead of means for introducing or circulating stretching medium into or through the bottom of the vessel, the apparatus may contain sprays for spraying the medium on the materials during their passage from the feed device to the delivery device in order to bring them to and maintain them in a suitable condition for stretching, and

for maintaining the materials in an unsoftened condition diuring the rest of their path through the vessel.

When the supply and take-up devices areoutside the vessel the materials may be sprayed with water or passed through water immediately before their entry into the vessel to assist in maintaining them in an unsoftened state during their passage through the inlet orifices.

When the materials are stretched during their travel through a substantially closed vessel between supply-and take-up devices positioned outside the vessel, they may enter the vessel either directly from the external atmosphere, or they may be passed first in contact with a positively driven feed device contained in a chamber filled with air or other inert fluid under pressure and communicating directly with the substantially closed vessel containing the stretching liquid. The use of this chamber reduces or eliminates any tension on the materials in the substantially closed'vessel due to fluid flow through the orifices by which they enter the vessel. A similar chamber may also be employed at the end of the vessel where the materials issue from it, but as explained in the above specifications it is, in general, of less value at this point.

The invention also includes the use of apparatus which comprises both means for cooling the atmosphere in the stretching vessel and also means for applying cooling fluid directly to the materials.

Apparatus such as is described above which comprises a closed or substantially closed vessel and a container for stretching fluid positioned in the vessel is novel and forms part of the pres ent invention.

The accompanying drawing illustrates diagrammatically the novel apparatus according to the present invention, wherein Figure 1 shows a vertical elevation of the apparatus; and

Figure 2 shows a horizontal cross-section on the line 2-2 of Fig. 1. f

Referring to Figures 1 and 2 the apparatus comprises a closed vessel 3 provided with an inlet 4 for compressed air and a pressure gauge 5. The lid 6 is detachable in ,order to allow'the introduction and removal of the supply bobbins I and the take-up bobbin 8. The bobbin 8 is provided with a friction disc 9 which is driven by another friction disc l fixed on a shaft H which carries a gear wheel l2 adapted to be driven in a suitable manner. The hot fluid is contained in a vessel l3 and its temperature is maintained by means of a steam coil M, the volunie of theliquid being maintained through a feed device l which is connected with means for supplying hot liquid to the vessel (not shown). Jets l6 are provided through which cold water may be sprayed on to the materials before and after their passage through the hot liquid, and the apparatus also comprises a catch tray I! connected with a pressure release valve 18 for removal of excess water. In operation the threads proceeding from the bobbins I pass over a guide [8' through a reed l9 to the nip rollers 20. After passing the nip rollers they are led by means of the guide rollers 2| under the surface of the hot fluid in the vessel and then pass through the nip rollers 22 and a reed 23 to a fixed guide 24 where the ends are brought together. From this guide they pass as a single end to the traverse guide 25 which lays them on the take-up bobbin 8. The. jets l6 may, if desired, be omitted.

Another form of apparatus according to the invention is one similar to that described above, but in which the bobbins and feed and delivery devices are outside the closed vessel, suitable orifices being provided in the ends for the entry and exit of the threads.

When stretching cellulose acetate yarn by means of the apparatus described above with reference to the drawing the container may be filled with hot water at a temperature of about 135 C., the total pressure in the vessel due to the steam and air may be about 40 pounds per square inch gauge and the materials may be stretched to about times their original length.

When hot water is employed as stretching medium it may be at a comparativelylow temperature, for example 105 C. or 110 C. or at a considerably higher temperature, for example 125, 135 or 140 C. or more, and the ressure in the vessel due to the compressed gas may, e. g. be 4, 6 or 10 pounds per square inch.

Solutions of softening agents may be employed instead of water. For example, the stretching medium may be a 30 to 45% solution of methyl alcohol at 80 to 100 C., a 1 to 8% solution of ethyl alcohol at 115 to 135 C. or a to 30% solution at 90 to- 100 C. Again, it may be a 30% solution of acetone at 100 to 110 C.

By means of the apparatus which forms the subject-matter of the present application it is possible to stretch artificial filaments, yarns and similar materials to 1,000 or 2,000% or more of their original length and to obtain products having a considerably increased tenacity and a good extensibility.

Having described our invention, what we desire to secure by Letters Patent is:

.1. Process for the treatment of artificial filaments, foils, films and similar materials, which comprises stretching them during their travel from one point to another and while they are in actual contact with a liquid medium which is at a temperature above its.boiling point at atmospheric pressure and which is contained in a closed or substantially closed vessel and maintaining within the vessel a pressure greater than that corresponding to the vapour pressure of the liquid medium at the said temperature by means of a gas in the vessel.

2. Process for the treatment of artificial filaments, foils, films and similar materials, which comprises stretching them during their travel from one point to another and while they are in actual contact with hot water which is at a temperature above its boiling point at atmospheric pressure and which is contained in a closed or substantially closed vessel and maintaining within the vessel a pressure greater than that corresponding to the vapor pressure of the water at the said temperature by means of a gas in the vessel. 7

3. Process for the treatment of artificial materials, which comprises stretching artificial filaments, foils, films and similar materials having a basis of an organic derivative of cellulose during their travel from one point to another and while they are in actual contact with hot water which is at a temperature above its boiling point at atmospheric pressure and which is contained in a closed or substantially closed vessel and maintaining within the vessel a pressure greater than that corresponding to the vapor pressure of the water at the said temperature by means of a gas in the vessel.

4. Process for the treatment of artificial maments, foils, films and similar materials having a basis of an organic derivative of cellulose durterials, which comprises stretching artificial filaing their travel from one point to another and while they are in actual contact with hot water which is at a temperature above its boiling point at atmospheric pressure and which is contained in a closed or substantially closed vessel and maintaining within the vessel a pressure greater than that corresponding to the vapor pressure of the water at the said temperature by means of a gas in the vessel, the materials being cooled before and after contact with the hot water.

5. Process for the treatment of artificial materials, which comprises stretching artificial filaments, foils, films and similar materials having a basis of cellulose acetate during their travel from one point to another and while they are in actual contact with hot water which is at a temperature above its boiling point at atmospheric pressure and which is contained in a closed or substantially closed vessel and maintaining within the vessel a pressure greater than that corresponding to. the vapor pressure of the water at the said temperature by means of a gas in the vessel.

6. Process for the treatment of artificial maa basis' ofcellulose acetate during their travel I from one p'ointto'another and while they are in actual contact with hot water which is at a temperatureabove its boiling point at atmospheri'c pressure and which is contained in a closed .or substantially closed vessel and main- *taining within the vessel a pressure greater than that corresponding tothe vapor pressure of the :wa'ter atthe said'tem'perature by means of ay 1 gas 'in-the vessel, the materials being cooledbe-- fore and after contact with the hot'water. 7 7. Ap'paratusiojr the? treatment ,of artificial) filaments, foils; films, similarf materials] which comprises a vessel for a gaseous medium under superatmospheric pressure having an inlet for gaseousmedium; a container for-stretching liquid positioned in said vessel, a feed device for 3 supplying stretching liquid to said container from a source exterior to said vessel and means for passing the materials through the stretching liquid and stretching them therein.

8. Apparatus for the treatment of artificial filaments, foils, films and similar materials, which comprises a vessel for a gaseous medium under superatmospheric pressure having an inlet for gaseous medium, a container for stretching liquid positioned in said vessel, a feed device for supplying stretching liquid to said container from a source exterior to said vessel and feed and delivery devices positioned in said vessel and adapted to pass the materials through the stretching liquid and stretch them therein.

9. Apparatus for the treatment of artificial filaments, foils, films and similar materials, which comprises a vessel for a gaseous medium under superatmospheric pressure having an inlet for gaseous medium, a container for stretching liquid positioned in said vessel, a feed device for supplying stretching liquid to said container from a source exterior to said vessel, means for cooling the materials before and after their contact with the stretching liquid and means for passing the materials through the stretching liquid and stretching them therein.

10. Apparatus for the treatment of artificial filaments, foils, films and similar materials,

which comprises a vessel for a gaseous medium under superatmospheric pressure having an inlet for gaseous medium, a container for stretching liquid positioned in said vessel, a feed device for supplying stretching liquid to said container from a source exterior to said vessel, means for cooling the materials before and after their contact with the stretchingliquid and feed and delivery devices positioned in said vessel and adapted to pass the materials through the stretching .liquid and, stretch them therein.

HENRY ams. ROBERT WIGHTON MONCRIEFF. 

